The eight wastes of Lean: DOWNTIME, explained with examples

DOWNTIME: the eight wastes

The usual memory aid spells DOWNTIME. Walk the process and ask, at each step, which of these is present.

• Defects: work done wrong, which costs twice, once to make the fault and again to fix it.
• Overproduction: making more, sooner or faster than the next step or the customer needs.
• Waiting: people, equipment or work sitting idle.
• Non-utilized talent: people closest to the work seeing its problems with no way to act on them.
• Transportation: unnecessary movement of material or information.
• Inventory: work held between steps, tying up space and money.
• Motion: unnecessary movement of people, such as reaching, walking and searching.
• Extra-processing: doing more than the requirement asks, such as tighter tolerances or approvals nobody reads.

Why overproduction is the worst

Overproduction generates the other wastes. Making too much creates inventory, which has to be moved and stored, and it hides defects: a fault in a large batch is discovered long after it was made, when everything done to those units since is also lost.

Inventory has the same hidden cost. The longer work waits between steps, the longer the gap between a defect being created and being found.

The same wastes in office work

The wastes apply just as much to knowledge and transactional work, where they are harder to see: documents waiting in queues, data re-entered between systems, approvals that add no scrutiny, and reports produced for nobody.

Value-adding, necessary and pure waste

Lean sorts activity into three kinds. Value-adding work transforms the product toward what the customer wants. Necessary non-value-adding work, such as regulatory checks and required inspections, cannot be removed yet and is reduced by changing the conditions that require it. Pure waste can be removed with no loss to the customer, which makes it the first target.

Inspection is the classic necessary non-value-adding step: it exists because defects are possible, and the real improvement is to make the defect impossible, not to inspect faster.

How the exams ask it

Questions describe a situation and ask which waste it shows, so learn to tell the close pairs apart: transportation moves things, motion moves people; inventory is work waiting, waiting is people or machines idle; extra-processing is doing more than required, while defects are doing it wrong.